This invention relates generally to storage containers and more particularly to containers designed for storing IC packages and IC package transport methods.
Tube-shaped storage containers of the prior art are generally shaped as shown in FIG. 4. Tube-shaped storage container 1 comprises a body section including a non-conductive transparent window 2 along the length of container 1 and a conductive portion 3 for purposes of grounding or otherwise removing generated static electricity from the IC packages stored in container 1.
As illustrated in FIG. 5, when storage container 1 containing IC packages 5 was inverted, contact and rubbing engagement between IC packages 5 and non-conductive transparent window 2 could not be avoided. Further, even if storage container 1 was carefully not inverted, vibration and movement during transport would result in such contact and rubbing engagement. As a result, the surface of IC packages 5 would become charged with static electricity and cause electrostatic damage to the IC chips sealed inside IC package 5.
The problem of static electricity generation relative to IC packages in such storage containers is the subject of Japanese Laid Open Utility Model Application 43911/89 to Okai et al., entitled, "Case for Storing Integrated Circuit Elements", published May 31, 1984. This Application discloses a storage container 10 having integrated conductive protrusions or projections 18 and 20 respectively in conductive regions or walls 15 and 19. Protrusions 18 and 20 were placed at strategic locations in the body of the IC container 10 in integrated combination with several transparent insulating, synthetic resin walls to aid in preventing IC packages 17 from becoming charged due to movement within container 10. Thus, IC packages 17 are supported for storage and transport by protrusions 18, providing for minimal contact area relative to container 10. As a result, static electricity was not easily generated since conductive protrusions functioned to ground any generated static electricity.
While Okai et al. was a step in the right direction, problems still remained. First, Okai et al. provided several transparent, insulating resin wall portions in the design of their container. These insulating portions of the container easily come in contact with corresponding insulating portions of other similar containers, such as during transport when several containers are packed together for shipment, or come in contact with other insulating objects and, in either case, causing the generation of static electricity and damage to the IC packages in the containers. The degree of damage caused by static electricity generated by contact between IC package containers can be just as bad as the damage caused by static electricity generated by contact between IC packages and insulating walls of an IC package container.
Secondly, the IC package containers of Okai et al. comprise a plurality of wall sections, some conductive resin and others insulating resin, that have to be bonded or otherwise secured together. In one example, there are eight such wall sections (FIGS. 4 and 5) and, in another example, there are twelve such wall sections. In the case of injection molding of such parts, it would be very difficult and expensive to mold together several different molded parts, particularly in the case of Okai et al. where the parts are alternated in conductive and insulating characteristics.
Third, the IC package containers of Okai et al. allow for lateral shifting of IC packages 17 permitting the leads of the packages to continuously engage the side walls of the container during transport which may bend the preformed IC package leads or even damage the packages per se.
It is an object of this invention to provide a container for the transport and storage of IC packages that is easy and cost effective to manufacture and yet insures the prevention of static electricity generation due to outside object engagement with the container as well as inside engagement of the IC packages with the container.
It is another object of this invention to provide a storage container for IC packages that concurrently prevents the contact or engagement of IC packages with nonconductive portions of the storage container and provides for minimum lateral movement of IC packages within the storage container.
It is another object of this invention to provide a method of transporting IC packages in a manner that prevents static electricity buildup on the IC packages due to container handling during their transport.